Planar close to a rear wall? Quad for example?

If its not common knowledge than it should be: all planar speakers need to be a minimum of 5 feet from the rear wall!

Any closer results in tonal colorations, the most pronounced being in the bass. Oddly, the only speaker I have seen that worked at all well at distances closer was indeed the '57, but invariably the owner was using a transistor amplifier, which cannot play bass on the speaker. Nevermind- the backwave reinforcement 'sort of' takes care of that. But put a good tube amp on a setup like that and the owner complains of too much one-note bass.

I used to have my Apogee Stages 18 inches from the wall
and they sounded fine--not boomy or compressed at all.
Maybe the soundstage was a somewhat flat but the tonality
and realism of the Stages was so awesome that I didn't care. I don't have them anymore because the left one's woofer broke.

I had to sell the Quad 63's I purchased from QS and D several weeks after I bought them as I couldnt pull them out more than 3.5 feet or so from the front wall.
Thought this would be enough before I bought them-- I had heard 3-6 feet was "ideal."
Once I had them in-house-- I realized it wasnt ideal whatsoever. No matter what position I tried them in or how much toe-in etc.-- couldnt get them to sound like I know I've heard them sound in a good set-up. Not even close. Dont waste your money until you've got the space.

Magnepan MC-1's are made to mount on the wall. I am running a pair on a wall that frames a picture window in front of my desk. I have the speakers about 5 feet apart and 4 feet from my listening position. Sandwiched between the speakers and the wall are acoustical panels (BAD) that are 18 inches by 48 inches high. I am supplementing the base with a quad sub. The tonal quality is very good but I struggle with imaging being so close to the speaker. Voices are good, but instruments tend to be smeared to the sides. It is not ideal but I cannot think of anything better given that I want to sit so close to the window/wall for the view while I work. I tried a pair of Gallo Due bookshelf speakers and they were waaay to "hot" sitting that close. The MC-1's are not too agressive at all, I just miss the imaging and depth.

Thanks for this Quad discussion and to Drken for starting it off. I was very favorably impressed by the musicality and dynamics (surprised is more accurate) of the new 2905 demo at the CES. A local dealer is adding the Quad line and I look forward to a more complete audition of both the 2805 and 2905 once he is set up.

The five feet minimum spacing from the front wall makes sense given the recommendation for at least a 10 ms delay between direct and first reflected sound arrival (I'm discounting floor bounce since we hear that anyway with speech or live music).

Mrtennis continues talking about his experiences with the 57, a different speaker from all later Quads because of radiation patterns and the heavy felt backing. I wouldn't question that he was impressed by a near-wall placement, but that is not relevant to the "new Quads" that Drken is asking about.

Overall, this is educational and fun reading.